diff options
Diffstat (limited to 'linuxnamespaces/__init__.py')
| -rw-r--r-- | linuxnamespaces/__init__.py | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/linuxnamespaces/__init__.py b/linuxnamespaces/__init__.py index b50f113..a39ab1d 100644 --- a/linuxnamespaces/__init__.py +++ b/linuxnamespaces/__init__.py @@ -136,6 +136,41 @@ class IDAllocation: """ return IDMapping(target, self.allocate(count), count) + def reserve(self, start: int, count: int) -> None: + """Reserve (and remove) the given range from this allocation. If the + range is not fully contained in this allocation, a ValueError is + raised. + """ + if count < 0: + raise ValueError("nagative count") + index = bisect.bisect_right(self.ranges, (start, float("inf"))) - 1 + if index < 0: + raise ValueError("range to reserve not found") + cur_start, cur_count = self.ranges[index] + assert cur_start <= start + if cur_start == start: + # Requested range starts at range boundary + if cur_count < count: + raise ValueError("range to reserve not found") + if cur_count == count: + # Requested range matches a range exactly + del self.ranges[index] + else: + # Requested range is a head of the matched range + self.ranges[index] = (start + count, cur_count - count) + elif cur_start + cur_count >= start + count: + # Requested range fits into a matched range + self.ranges[index] = (cur_start, start - cur_start) + if cur_start + cur_count > start + count: + # Requested range punches a hole into a matched range + self.ranges.insert( + index + 1, + (start + count, cur_start + cur_count - (start + count)) + ) + # else: Requested range is a tail of a matched range + else: + raise ValueError("range to reserve not found") + def newidmap( kind: typing.Literal["uid", "gid"], |